TABLE VIII.

PARALLAX OF THE SUN ON THE FIRST DAY OF EACH MONTH, THE MEAN HORIZONTAL PARALLAX BEING 8" 60.

The Sun's Horizontal Parallax is also given for every ten days, in the Nautical Alma

nac, immediately before the ephemeris of the planets.

The Sun's Parallax in Altitude, for every degree, is given in the last of Dr. Pearson's "Solar Tables," vol. i. page 180.

TABLE IX.

REDUCTION OF THE MOON'S EQUATORIAL HORIZONTAL PARALLAX, TO THE HORIZONTAL PARALLAX IN ANY LATITUDE.

The Moon's Horizontal Parallax, given in the third page of each month in the Nautical Almanac for noon and midnight, is the equatorial parallax for Greenwich mean noon and midnight; from thence it is to be deduced for the time and place of observation. The correction for latitude, on account of the spherical figure of the earth, is seldom thought of at sea, but can be made from the table above. Thus, supposing the hor. equat. par. to be 58'; the hor: par. in lat. 52° would be 58′7′′-2 57' 52"8.

This reduced hor. par. is to be farther corrected for altitude by means of tables for that purpose (see Pearson, vol. i. pages 188 to 196: and Riddle, pages 156* to 173); or by the following rule:-sin hor. par. X cos alt. sine par. in alt.

=

* Riddle's tables are for clearing the lunar distance, and the corrections are for both parallax and refraction.

The Parallaxes and Semidiameters of the Planets are given in the Nautical Almanac.

DIP OF THE SEA HORIZON AT DIFFERENT DISTANCES FROM IT.

0 0-0 2-0 7.8

17.7

31.4

49.1

70-7

1

0-0 2-0

8.0

17.9

31.7

49-4

71.1

2 0.0 2.1 8.1

18-1

31.9

49-7

71.5

3

9.0 2.2

96.2 125-7 1590 196-3 237.5 282-7 331-8 384-7 96.7 126-2 159-6 197-0 238-3 283-5 332-6 385-6 97.1 126-7 160-2 197-6 239-0 284-2 333-4 386-6 97-6 127-2 160 8 198-3 239-7 285-0 334-3 387-5 98-0 127-8 161-4 198-9 240-4 2858 335.2 388-4 98.5 128-3 1620 1996 241-2 2866 336-0 389-3 99-0 128-8 162-6 2003 241-9 287-4 336-9 390-2 99-4 129-3 163.2 200-9 242-6 288-2 337-7 391-1 73.9 99-9 129-9 163-8 2016 243.3 2890 338-6 392 1 19.5 33.8 52.1 74.3 100-4 130-4 1644 202-2 289-8 3394 393-0 19.7 34.1 52.4 74.7 100-8 131-0 165.0 202-9 19-9 34.4 52.7 75.1 101.3 131.5 165'6 2036 20.1 34.6 53.1 75.5 101-8 132 0 166.2 204 2 246.3 292-2 342-0 395.8 20.3 34.9 53.4 75.9 102.3 132.6 166-8 204-9 2470 2930 342-9 396-7 20.5 35.2 53.8 76.3 102.7 133.1 167-4 2056 247-7 2938 343.7 397-6 20.7 35.5 54.1 76.7 103.2 133-6 168.0 2063 248'5 294 6 344 6 398'6 10.1 20-9 103-7 134-2 1686 206-9 2492 295-4 345-5 399-5 17 0-2 3-2 10-2 134-7 169-2 2076 249-9 296-2 3464 4005 18 0-2 3-3 10.4 135 3 169-8 208 3 250-7 19 0-2 34 10.5 135-8 170-4 208-9 251 4 20 0.2 3.5 10.7 136-3 171-0 2096 21 0.2 36 10.8 1369 171-6 2103 253-0 22 0.3 37 11.0 106.6 137 4 172-2 2110 253-6 300 2 350-7 405.1 23 0-3 3-8 11.2 107-0 1380 172-9 211-7 254-4 3010 351-6 406-0 24 0-3 3-8 11.3 107.5 138.5 173.5 212-3 255 1 301-8 352-5 407-0 25 0-3 39 11.5 1080 1391 174-1 213-0 255-9 302 6 353 3 408'0 26 0-4 4-0 11.6 1085 139'6 174-7 2137 2566 303-5 354-2 408.9 27 0-4 4-1 11.8 109 0 140 2 175-3 214-4 257-4 304-3 3551 409-9 28 0.4 4.2 11.9 1095 1407 175-9 215-1 258.1 305 1 356 0 410-8 110-0 141-3 176.6 2158 258-9 305-9 356-9 4117 110-4 141-8 177-2 216-4 259-6 3067 357-7 412-7 110-9 142-4 177-8 2171 260 4 307 5 358 6 413-6 111-4 1430 178-4 217-8 261-1 308 4 359-5 414-6 111-9 143-5 179-0 218-5 261-9 309-2 360-4 415-5 112-4 144-1 179-7 219-2 262-6 3100 361 3 416-5 112.9 144 6 180 3 219-9 263-4 3108 362-2: 417-5 113.4 145-2 180-9 220'6 264.1 3116 363 1 418-4 113.9 145-8 181-6 221-3 264-9 312-5 364-0 419-3 114-4 146.3 182.2 2220 265-7 313-3 364-8 420-3 114-9 146-9 182-8 222-7 266-4 3141 3657 421-3 115 4 147.5 183-5 223-4 267-2 3150 366'6 422-2 115.9 148 0 184 1 224-1 267-9 315-8 367-5 423-2 116 4 148-6 184-7 224-8 268-7 3166 368 4 424-2 116-9 149-2 185-4 225-5 269-5 317-4 369-3 425-1 117-4 149-7 186-0 226-2 270-3 318-3 370-2 426 F 117.9 150-3 186-6 226-9 271-0 319-1 371-1 427-0 118-4 150 9 187-3 227-6 271-8 319-9 372-0 428-0 118.9 151-5 187-9 228-3 272-6 3208 3729 429-0 119.5 152-0 188.5 2290 273-3 3216 373-8 429-9 1200 152-6 189-2 2297 274-1 322-4 374-7 430-9 120.5 153.2 189-8 230-4 274.9 323-3 375-6 431.9 121-0 153-8 190-5 231-1 275'6 324-1 376-5 432-8 121-5 154-4 191-1 231-8 276.4 325 0 377-4 433-8 122.0 154.9 191-8 232-5 277.2 325-8 378-3 434-8. 122.5 155-5 192-4 233-2 2780 326-7 379-3 435-8 123-1 156-1 193-1 234-0 278-8 327 5 380 2 436-7 123.6 156-7 1937 2347 279-5 328 4 381.1 437-7 124.1 157-3 194 4 235 4 280-3 329 2 382-0 438-7 124.6 157-8 195-0 236-1 281 1 330-0 382-9 439-7 125 1 158.4 195-7 236-8 281-9 330-9 383-8 440-6

35'7

54.5

77.1

21.2 36'0

54.8

77-5

104-2

21.4 36.3

55.1

779

104 6

78.3

105 1

43'7 64.2 27.4 44'0 64.5 11 60 14.8 27.6 44'3 64.9 46 12 61 15'0 27.9 44'6 65.3 47 1.2 6.2 15.2 28.1 44'9 65*7 48 1.3 64 15:4 28.3 45'2 66'0 90-8 49 1.3 6.5 15-6 28.6 45'5 66'4 91.2 50 1.4 6.6 15'8 28.8 45'9 66'8 91.7 51 1-4 6-7 15.9 29.1 46'2 67.2 92.1 52 1.5 6.8 16'1 29.4 46'5 67.6 92.6 53 1.5 7.0 16.3 29.6 46'8 68.0 93'0 54 1.6 7.1 16.5 29.9 47'1 68.3 93.5 55 1.6 7.2 16.7 30.1 47'5 68.7 93.9 56 1.7 7.3 16.9 30-4 47'8 69.1 94.4 57 1.8 7.5 17.1 30.6 48'1 69.5 94.8 58 18 7.6 17.3 30.9 48°4 69.9 95.3 59 1.9 7.7 17.5 31.1 48.8 70.3 95.7

Table XVIII. of Mr. Baily extends to 36 minutes from the meridian.